If none of the above solutions works for you - create a new administrator user and repeat the steps under the new account. You will have to transfer all the existing data to the new user profile from the old one.

UPDATE Thanks to Matthew in the comments. Many people are complaining about this error: + FullyQualifiedErrorId : DeploymentError,Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand. This link link seem to resolve this problem.